Both parties involved in a call include a calling party and a called party. After the calling party initiates a call request, the called party is paged through network. After a channel for transmitting a voice packet is established, the calling party and the called party may start a call. Generally, cost of the call is paid or mainly paid by the calling party, the network can identify the calling party and the called party, and charge the calling party according to the traffic or talk time, and the called party may not need to pay cost or only need to pay less.
In real life, there is a scene that the calling party needs to call the called party, while the calling party can afford limited cost and the called party can provide sufficient tariffs. If the current call continues, the network may interrupt the current call due to tariff problems of the calling party; and if the two parties of the call expect to continue the call, one of the calling party and the called party needs to take the initiative to hang up, and then the previous called party starts a call as a calling party, and pages the previous calling party, after establishing a channel for transmitting voice data packets, the two parties re-engage the call, which makes user experience of both parties uncomfortable.
In a conventional technology, a current call needs to be terminated firstly, and then roles of calling and called parties need to be modified to re-establish a new call, which makes operation complicated. In addition, signaling overhead is large for a network and user experience of both parties of the call is not comfortable.